This invention relates to an improved shutter controlling the beam of a high power laser.
When the output beam of a high power continuously operating laser is temporarily switched off or interrupted in the normal operation of associated apparatus or systems, dissipation of energy during the interruption period presents a problem simply because of the extremely high power densities involved. For example, the Nd:YAG type laser on which this device was first used produces a 6 mm diameter beam having a power density of up to 4.4 killowatts per square centimeter. Prior art practice has been to move a reflector into the beam path and reflect the beam through a fixed optical expander lens into an appropriate absorber such as oxidized aluminum. The expander lens effectively reduces the power density in the beam to a level that may be dissipated safely and without damage to the absorber. The expander lens is not only an expensive component but also tends to collect dust particles which interfere with the dissipation function. Furthermore, mounting and alignment of the lens between the reflector and absorber is an additional cost factor in the construction of the associated apparatus.